Rapid preheating for extrusion-type additive manufacturing of super-engineering thermoplastics

This study presents an in-situ infrared (IR) heating approach to enhance the print quality of polyetherimide (PEI) parts fabricated via high-temperature material extrusion (MEX). A custom MEX system equipped with dual IR lamps was developed to maintain localized heating near the nozzle during deposition. Thermal analysis confirmed that IR heating effectively sustained the surface temperature of the printed layers above the glass transition temperature (177 °C), improving molecular diffusion across interfaces. Experimental results demonstrated that IR-assisted printing significantly reduced warping deformation and enhanced tensile strength, particularly in the transverse direction, thereby alleviating the anisotropic behavior typically observed in MEX-printed parts. Fractographic analysis using scanning electron microscopy revealed improved interlayer bonding and reduced voids with increasing IR power. However, excessive IR input slightly decreased the longitudinal strength, indicating the presence of an optimal IR power range. This work highlights the importance of thermal control in high-temperature polymer printing and suggests that in-situ IR heating is an effective strategy for improving the mechanical performance and dimensional stability of super engineering plastics such as PEI.